title: Human placental alkaline phosphatase: expression in Pichia pastoris, purification and characterization of the enzyme.
abstract: The soluble form of human placental alkaline phosphatase (PLAP) was expressed in the methylotrophic yeast Pichia pastoris and the expression product was purified and characterized. Yeast-derived PLAP (yPLAP) was secreted into the medium to the level of 2 mg/liter. yPLAP displayed kinetic properties similar to those reported earlier for the membrane-bound PLAP. Purified yPLAP had specific activity of 774 U/mg and appeared in two subunit sizes, ca. 62 and 65 kDa. This difference was due to heterogenous N-glycosylation. Purified yPLAP appeared as multiple forms in isoelectric focusing in pI range of 4.2 to 5.2. The expression system is discussed in comparison to previously reported expression systems.
authors.affiliation: Department of Biochemistry and Food Chemistry, University of Turku, Turku, FIN-20014, Finland. heihei@utu.fi
authors.forename: H
authors.initials: H
authors.lastname: Heimo
authors.forename: K
authors.initials: K
authors.lastname: Palmu
authors.forename: I
authors.initials: I
authors.lastname: Suominen
mesh_terms: D000469:Alkaline Phosphatase / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification*; D000595:Amino Acid Sequence; D001483:Base Sequence; D004247:DNA / Q000235:genetics; D005260:Female; D015870:Gene Expression; D006031:Glycosylation; D006801:Humans; D007526:Isoelectric Point; D007700:Kinetics; D008970:Molecular Weight; D009838:Oligodeoxyribonucleotides / Q000235:genetics; D010843:Pichia / Q000235:genetics*; D010920:Placenta / Q000201:enzymology*; D011247:Pregnancy; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification
chemical_list: D009838:Oligodeoxyribonucleotides; D011994:Recombinant Proteins; D004247:DNA; D000469:Alkaline Phosphatase